1. Field of the Invention
The present invention relates to a system for image display and photographing.
2. Description of the Related Art
Recent years have seen the widespread use of projectors which projects, onto a screen, an image displayed in a personal computer or smartphone. Such a projector is sometimes called an “image projection device”.
The screen may be a whiteboard. The screen may be a white plastic sheet put on a wall. In such cases, a user may take a note on the screen with a pen while an image is projected onto the screen. The user may take a photo of the screen with a digital camera for recording.
There has been proposed a technology which allows a user to take a photo easily. According to the technology, a projector has a digital camera built therein, and a lens for projection to a liquid crystal projector and a lens for the digital camera are used in common. Thereby, both the projected light of the video by a personal computer outputted from the projector and the incident light of a synthetic image of the image handwritten by using a marker pen or the like on a whiteboard pass through the same lens. This eliminates, in importing the synthetic video of the video by the personal computer and the handwritten image to the personal computer, the need to adjust the position and size thereof (English abstract of Japanese Laid-open Patent Publication No. 2004-252118).
Another technology has been proposed for changing an image displayed at a time when a user touches a predetermined position in a display surface (Japanese Laid-open Patent Publication No. 2005-242725). Yet another technology has been proposed for controlling the driving of a projector. According to the technology, it is detected whether or not a human is present in a drawing region where a projector draws an image; and the driving of the projector is so controlled as to change an image or an image pattern plotted in the drawing area depending on whether or not the human is detected in the drawing region (Japanese Laid-open Patent Publication No. 2011-107237).
It is bothersome for a user to operate a button of a projector while making a presentation. This is because, during the presentation, the user is a little away from the projector. The user is often next to a screen during the presentation.
In view of this, it would be convenient to enter a command into the projector by doing something on the screen. It would be also convenient to enter a photographing command by doing something on the screen. For example, a button corresponding to the photographing command is displayed together with an image on the screen. In response to the button touched, a digital camera takes an image.
According to this method, unfortunately, a user's human body is sometimes photographed above the image.